Inflammatory Systemic Biomarkers in Setting Acute Coronary Syndromes - Effects of the Diurnal Variation

The role of incretins and incretin-based drugs in autoimmune diseases

Incretin hormones, including glucagon-like peptide (GLP)-1, GLP-2 and glucose-dependent insulinotropic polypeptide (GIP), are gastrointestinal peptides secreted from enteroendocrine cells. These hormones play significant roles in many physiological processes via binding to G-protein coupled receptors (GPCRs) on different organs and tissues; one of them is the immunomodulatory effect on the immune system and its molecular components such as cytokines and chemokines. Anti-inflammatory effects of incretins and dependent molecules involving long-acting analogs and DPP4 inhibitors through regulation of T and B cell activation may attenuate autoimmune diseases caused by immune system disorders in mistakenly recognizing self as the foreign agent. In this review, we investigate incretin effects on the immune system response and the potential benefits of incretin-based therapy for treating autoimmune diseases.

MarkVCID cerebral small vessel consortium: I. Enrollment, clinical, fluid protocols

The concept of vascular contributions to cognitive impairment and dementia (VCID) derives from more than two decades of research indicating that (1) most older individuals with cognitive impairment have post mortem evidence of multiple contributing pathologies and (2) along with the preeminent role of Alzheimer's disease (AD) pathology, cerebrovascular disease accounts for a substantial proportion of this contribution. Contributing cerebrovascular processes include both overt strokes caused by etiologies such as large vessel occlusion, cardioembolism, and embolic infarcts of unknown source, and frequently asymptomatic brain injuries caused by diseases of the small cerebral vessels. Cerebral small vessel diseases such as arteriolosclerosis and cerebral amyloid angiopathy, when present at moderate or greater pathologic severity, are independently associated with worse cognitive performance and greater likelihood of dementia, particularly in combination with AD and other neurodegenerative pathologies. Based on this evidence, the US National Alzheimer's Project Act explicitly authorized accelerated research in vascular and mixed dementia along with frontotemporal and Lewy body dementia and AD itself. Biomarker development has been consistently identified as a key step toward translating scientific advances in VCID into effective prevention and treatment strategies. Validated biomarkers can serve a range of purposes in trials of candidate interventions, including (1) identifying individuals at increased VCID risk, (2) diagnosing the presence of cerebral small vessel disease or specific small vessel pathologies, (3) stratifying study participants according to their prognosis for VCID progression or treatment response, (4) demonstrating an intervention's target engagement or pharmacodynamic mechanism of action, and (5) monitoring disease progression during treatment. Effective biomarkers allow academic and industry investigators to advance promising interventions at early stages of development and discard interventions with low success likelihood. The MarkVCID consortium was formed in 2016 with the goal of developing and validating fluid- and imaging-based biomarkers for the cerebral small vessel diseases associated with VCID. MarkVCID consists of seven project sites and a central coordinating center, working with the National Institute of Neurologic Diseases and Stroke and National Institute on Aging under cooperative agreements. Through an internal selection process, MarkVCID has identified a panel of 11 candidate biomarker "kits" (consisting of the biomarker measure and the clinical and cognitive data used to validate it) and established a range of harmonized procedures and protocols for participant enrollment, clinical and cognitive evaluation, collection and handling of fluid samples, acquisition of neuroimaging studies, and biomarker validation. The overarching goal of these protocols is to generate rigorous validating data that could be used by investigators throughout the research community in selecting and applying biomarkers to multi-site VCID trials. Key features of MarkVCID participant enrollment, clinical/cognitive testing, and fluid biomarker procedures are summarized here, with full details in the following text, tables, and supplemental material, and a description of the MarkVCID imaging biomarker procedures in a companion paper, "MarkVCID Cerebral small vessel consortium: II. Neuroimaging protocols." The procedures described here address a range of challenges in MarkVCID's design, notably: (1) acquiring all data under informed consent and enrollment procedures that allow unlimited sharing and open-ended analyses without compromising participant privacy rights; (2) acquiring the data in a sufficiently wide range of study participants to allow assessment of candidate biomarkers across the various patient groups who might ultimately be targeted in VCID clinical trials; (3) defining a common dataset of clinical and cognitive elements that contains all the key outcome markers and covariates for VCID studies and is realistically obtainable during a practical study visit; (4) instituting best fluid-handling practices for minimizing avoidable sources of variability; and (5) establishing rigorous procedures for testing the reliability of candidate fluid-based biomarkers across replicates, assay runs, sites, and time intervals (collectively defined as the biomarker's instrumental validity). Participant Enrollment Project sites enroll diverse study cohorts using site-specific inclusion and exclusion criteria so as to provide generalizable validation data across a range of cognitive statuses, risk factor profiles, small vessel disease severities, and racial/ethnic characteristics representative of the diverse patient groups that might be enrolled in a future VCID trial. MarkVCID project sites include both prospectively enrolling centers and centers providing extant data and samples from preexisting community- and population-based studies. With approval of local institutional review boards, all sites incorporate MarkVCID consensus language into their study documents and informed consent agreements. The consensus language asks prospectively enrolled participants to consent to unrestricted access to their data and samples for research analysis within and outside MarkVCID. The data are transferred and stored as a de-identified dataset as defined by the Health Insurance Portability and Accountability Act Privacy Rule. Similar human subject protection and informed consent language serve as the basis for MarkVCID Research Agreements that act as contracts and data/biospecimen sharing agreements across the consortium. Clinical and Cognitive Data Clinical and cognitive data are collected across prospectively enrolling project sites using common MarkVCID instruments. The clinical data elements are modified from study protocols already in use such as the Alzheimer's Disease Center program Uniform Data Set Version 3 (UDS3), with additional focus on VCID-related items such as prior stroke and cardiovascular disease, vascular risk factors, focal neurologic findings, and blood testing for vascular risk markers and kidney function including hemoglobin A1c, cholesterol subtypes, triglycerides, and creatinine. Cognitive assessments and rating instruments include the Clinical Dementia Rating Scale, Geriatric Depression Scale, and most of the UDS3 neuropsychological battery. The cognitive testing requires ≈60 to 90 minutes. Study staff at the prospectively recruiting sites undergo formalized training in all measures and review of their first three UDS3 administrations by the coordinating center. Collection and Handling of Fluid Samples Fluid sample types collected for MarkVCID biomarker kits are serum, ethylenediaminetetraacetic acid-plasma, platelet-poor plasma, and cerebrospinal fluid (CSF) with additional collection of packed cells to allow future DNA extraction and analyses. MarkVCID fluid guidelines to minimize variability include fasting morning fluid collections, rapid processing, standardized handling and storage, and avoidance of CSF contact with polystyrene. Instrumental Validation for Fluid-Based Biomarkers Instrumental validation of MarkVCID fluid-based biomarkers is operationally defined as determination of intra-plate and inter-plate repeatability, inter-site reproducibility, and test-retest repeatability. MarkVCID study participants both with and without advanced small vessel disease are selected for these determinations to assess instrumental validity across the full biomarker assay range. Intra- and inter-plate repeatability is determined by repeat assays of single split fluid samples performed at individual sites. Inter-site reproducibility is determined by assays of split samples distributed to multiple sites. Test-retest repeatability is determined by assay of three samples acquired from the same individual, collected at least 5 days apart over a 30-day period and assayed on a single plate. The MarkVCID protocols are designed to allow direct translation of the biomarker validation results to multicenter trials. They also provide a template for outside groups to perform analyses using identical methods and therefore allow direct comparison of results across studies and centers. All MarkVCID protocols are available to the biomedical community and intended to be shared. In addition to the instrumental validation procedures described here, each of the MarkVCID kits will undergo biological validation to determine whether the candidate biomarker measures important aspects of VCID such as cognitive function. Analytic methods and results of these validation studies for the 11 MarkVCID biomarker kits will be published separately. The results of this rigorous validation process will ultimately determine each kit's potential usefulness for multicenter interventional trials aimed at preventing or treating small vessel disease related VCID.

Reward Responsiveness and Ruminative Styles Interact to Predict Inflammation and Mood Symptomatology

Abnormal reward responsiveness and rumination each are associated with elevated inflammation and mood symptoms. Ruminating on positive and negative affect, or dampening positive affect, may amplify, or buffer, the associations of reward hyper/hyposensitivity with inflammation and mood symptoms. Young adults (N = 109) with high or moderate reward sensitivity completed reward responsiveness and ruminative style measures at the initial visit of a longitudinal study of mood symptoms, a blood draw to assess inflammatory biomarkers, and mood symptom measures at the study visits before and after the day of the blood draw. The interaction between high reward responsiveness and rumination on positive affect was associated with higher levels of an inflammatory composite measure and hypomanic symptoms. The interaction between lower reward responsiveness and high dampening of positive affect was associated with higher levels of the inflammatory composite measure and depressive symptoms. Lower reward responsiveness also interacted with low rumination on positive affect to predict increases in depressive symptoms and higher levels of the inflammatory composite. Thus, levels of reward responsiveness and ruminative response styles may synergistically influence the development of inflammatory phenotypes and both hypomanic and depressive mood symptoms.

Bidirectional Associations Between Inflammatory Biomarkers and Depressive Symptoms in Adolescents: Potential Causal Relationships

There are inconsistent findings in the literature about the directionality and magnitude of the association between inflammation and depressive symptoms. This analysis separates predictors into between-person and within-person components to gain greater clarity about this relationship. Blood samples were collected and depressive symptoms assessed in 140 adolescents (54% female, 59% Black, Mage = 16.1 years) with at least three blood draws and a total of 394 follow-up observations. Multi-level modeling indicated that the within-person effect of tumor necrosis factor alpha (TNF-α) predicted change in total depressive symptoms, suggesting a potential causal relationship. There were no significant within-person effects of total depressive symptoms on change in biomarkers. Exploratory analyses examined associations between inflammatory biomarkers and subsets of depressive symptoms. These findings inform modeling decisions that may explain inconsistencies in the extant literature as well as suggest potential causal relationships between certain proteins with significant within-person effects on depressive symptoms, and vice-versa.

Association between Upper-airway Surgery and Ameliorative Risk Markers of Endothelial Function in Obstructive Sleep Apnea

The objective of our study was to evaluate the effects of upper-airway surgery on improvement of endothelial function-related markers in patients with obstructive sleep apnea (OSA). Subjects with moderate to severe OSA who underwent upper-airway surgery, with a follow-up duration of at least 6 months, were included. Pre- and postoperative polysomnographic variables and endothelial function-related markers were compared. Subgroup and correlation analyses were conducted to find possible indicators for better endothelial function-related markers after upper-airway surgery. In total, 44 patients with OSA were included. The mean follow-up duration was 1.72 ± 0.92 years. Serum VEGFA [-20.29 (CI: -35.27, -5.31), p < 0.05], Ang2 [-0.06 (CI: -0.16, 0.03), p < 0.05], E-selectin [-7.21 (CI: -11.01, -3.41), p < 0.001], VWF [-58.83 (CI: -103.93, -13.73), p < 0.05], VWFCP [-33.52 (CI: -66.34, -0.70), p < 0.05], and TM [-0.06 (CI: -0.09, -0.03), p < 0.05] were significantly lower after upper-airway surgery. However, other risk markers of endothelial function, such as Ang1, ICAM1, VEGFR1, and VCAM, did not change significantly. Correlations between improved endothelial function-related markers and ameliorated oxyhemoglobin saturation and glucolipid metabolism were established. Upper-airway surgery might be associated with an improvement in endothelial function in patients with OSA. These changes may be associated with improved oxygen saturation after upper-airway surgery.

Immunocognitive Model of Depression Secondary to Anxiety in Adolescents

There is evidence that anxiety precedes the onset of depression and that rumination contributes to this risk pathway in adolescence. This study examined inflammatory biomarkers as mediators in a risk model of depressive symptoms secondary to anxiety symptoms among adolescents who ruminate. A sample of 140 adolescents (52% female, 54% African American, 40% Caucasian, 6% biracial, mean age at T1 = 16.5 years, SD = 1.2 years) provided blood samples on two visits (T1 and T2; mean time between T1 and T2 = 13.5 months, SD = 5.9 months). Self-report anxiety, depression, and rumination measures were given at T1 and the depression measure was given again at a third visit (T3, mean months since T1 = 26.0 months, SD = 9.0 months). Higher anxiety predicted more interleukin-6, but not more C-reactive protein, for adolescents with high levels of rumination. Moderated mediation analyses (N for analysis after removing cases with missing data and outliers = 86) indicated that interleukin-6, but not C-reactive protein, at T2 mediated the relationship between anxiety symptoms at T1 and depressive symptoms at T3, conditional on rumination. Anxiety and rumination interacted such that, as rumination increased, anxiety predicted greater inflammation and depressive symptoms. These results demonstrate that established cognitive vulnerabilities for the development of depressive symptoms secondary to anxiety symptoms in adolescence might indirectly operate though biological mechanisms such as inflammation. In addition to highlighting risk factors and potential treatment targets for depression, this study suggests a potential biological mechanism underlying the effects of psychotherapies that reduce rumination on negative affect (e.g., cognitive behavioral therapy).

Association of pre-admission statin therapy and the inflammatory response in ST elevation myocardial infarction patients

PURPOSE

To demonstrate the possible association of statin therapy with C reactive protein (CRP) serial measurements in ST elevation myocardial infarction (STEMI) patients.

MATERIALS AND METHODS

STEMI patients between 2008 and 2016 with available CRP data from admission were divided into two groups according to pre-admission statin therapy. A second CRP measurement was noted following primary coronary intervention (within 24 h from admission). The difference between the two measurements was designated ΔCRP.

RESULTS

The cohort consisted of 1134 patients with a median age of 61 (IQR52-70), 81% males. Patients on statins prior to admission (336/1134, 26%) were more likely to have CRP levels within normal range (≤5 mg/l) compared to patients without prior treatment, both at admission (75 vs. 24%, p = 0.004) and at 24 h (70 vs. 48%, p = 0.029). The prevalence of patients with pre-admission statin therapy decreased as ΔCRP increased (p = 0.004; n = 301). The likelihood of ΔCRP to be above 5 mg/l in patients with pre-admission statin therapy was reduced after age and gender adjustments (OR 0.54, 95% CI 0.32-0.92, p = 0.023) and in multivariate (OR 0.57, 95% CI 0.33-0.99, p = 0.048) analysis.

CONCLUSIONS

Pre-admission statin therapy is associated with a less robust inflammatory response in STEMI patients, highlighting statin's pathophysiological importance.

Prediction of risk of cardiovascular events in patients with mild to moderate coronary artery lesions using naïve Bayesian networks

BACKGROUND

This prospective study integrated multiple clinical indexes and inflammatory markers associated with coronary atherosclerotic vulnerable plaque to establish a risk prediction model that can evaluate a patient with certain risk factors for the likelihood of the occurrence of a coronary heart disease event within one year.

METHODS

This study enrolled in 2686 patients with mild to moderate coronary artery lesions. Eighty-five indexes were recorded, included baseline clinical data, laboratory studies, and procedural characteristics. During the 1-year follow-up, 233 events occurred, five patients died, four patients suffered a nonfatal myocardial infarction, four patients underwent revascularization, and 220 patients were readmitted for angina pectoris. The Risk Estimation Model and the Simplified Model were conducted using Bayesian networks and compared with the Single Factor Models.

RESULTS

The area under the curve was 0.88 for the Bayesian Model and 0.85 for the Simplified Model, while the Single Factor Model had a maximum area under the curve of 0.65.

CONCLUSION

The new models can be used to assess the short-term risk of individual coronary heart disease events and may assist in guiding preventive care.

Effect of Serum Growth Differentiation Factor-15 and the Syntax Score on 2-Year Outcomes in Patients With Acute Coronary Syndrome

Growth differentiation factor-15 (GDF-15) is produced by cardiomyocytes and atherosclerotic lesions under stress conditions, but little is known about its relation with severity and complexity of coronary lesions. The aim of this study was to investigate the association between GDF-15 and the syntax score for risk prediction of major adverse cardiovascular events (MACE) at 2-year follow-up in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). This is a prospective cohort study of 502 patients with NSTEACS. The syntax score was calculated from baseline coronary angiography. Blood samples were obtained at study entry for the assessment of GDF-15 and high-sensitivity C reactive protein. One hundred and three patients (20.5%) showed MACE at 2-year follow-up. Patients who developed MACE had greater GDF-15 concentrations and syntax score (p <0.001) compared to patients who did not. There was a positive, but moderate, correlation between GDF-15 and syntax score (ρ = 0.45, p <0.0001). On Cox regression analysis, only GDF-15 levels (p <0.001), body mass index (p = 0.04), and syntax score (p <0.001) remained independent predictors of the MACE. The area under the curve of GDF-15 (0.912, 95% confidence interval 0.894 to 0.944) was significantly greater compared to high-sensitivity C reactive protein and syntax score. In conclusion, in patients with NSTEACS, levels of GDF-15 at admission were correlated with the syntax score and independently associated with an increased risk of MACE during 2-year follow-up.

Short-term effects of air pollution, markers of endothelial activation, and coagulation to predict major adverse cardiovascular events in patients with acute coronary syndrome: insights from AIRACOS study

The aim of this study was to determine whether markers of inflammation and coagulation are associated with short-term particulate matter exposure and predict major adverse cardiovascular events at 360 d in patients with acute coronary syndrome (ACS). We included 307 consecutive patients, and assessed the average concentrations of data on atmospheric pollution in ambient air and meteorological variables from 1 d up to 7 d prior to admission. In patients with ACS, the markers of endothelial activation and coagulation, but not black carbon exposure, are associated with major adverse cardiovascular events at one-year follow-up.

Change in growth differentiation factor 15, but not C-reactive protein, independently predicts major cardiac events in patients with non-ST elevation acute coronary syndrome

Among the numerous emerging biomarkers, high-sensitivity C-reactive protein (hsCRP) and growth-differentiation factor-15 (GDF-15) have received widespread interest, with their potential role as predictors of cardiovascular risk. The concentrations of inflammatory biomarkers, however, are influenced, among others, by physiological variations, which are the natural, within-individual variation occurring over time. The aims of our study are: (a) to describe the changes in hsCRP and GDF-15 levels over a period of time and after an episode of non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and (b) to examine whether the rate of change in hsCRP and GDF-15 after the acute event is associated with long-term major cardiovascular adverse events (MACE). Two hundred and Fifty five NSTE-ACS patients were included in the study. We measured hsCRP and GDF-15 concentrations, at admission and again 36 months after admission (end of the follow-up period). The present study shows that the change of hsCRP levels, measured after 36 months, does not predict MACE in NSTEACS-patients. However, the level of GDF-15 measured, after 36 months, was a stronger predictor of MACE, in comparison to the acute unstable phase.

TREM-1 and pentraxin-3 plasma levels and their association with obstructive sleep apnea, obesity, and endothelial function in children

BACKGROUND

Obstructive sleep apnea (OSA) is a common health problem in children and increases the risk of cardiovascular disease (CVD). Triggering receptor expressed on myeloid cells-1 (TREM-1) plays an important role in innate immunity and amplifies inflammatory responses. Pentraxin-3 is predominantly released from macrophages and vascular endothelial cells, plays an important role in atherogenesis, and has emerged as a biomarker of CVD risk. Thus, we hypothesized that plasma TREM-1 and pentraxin-3 levels would be elevated in children with OSA.

METHODS

ONE HUNDRED SIX CHILDREN (MEAN AGE: 8.3 ± 1.6 y) were included after they underwent overnight polysomnographic evaluation and a fasting blood sample was drawn the morning after the sleep study. Endothelial function was assessed with a modified hyperemic test after cuff-induced occlusion of the brachial artery. Plasma TREM-1 and pentraxin-3 levels were assayed using commercial enzyme-linked immunosorbent assay kits. Circulating microparticles (MPs) were assessed using flow cytometry after staining with cell-specific antibodies.

RESULTS

Children with OSA had significantly higher TREM-1 and pentraxin-3 levels (versus controls: P < 0.01, P < 0.05, respectively). Plasma TREM-1 was significantly correlated with both body mass index (BMI)-z score and the obstructive apnea-hypopnea index (AHI) in univariate models. Pentraxin-3 levels were inversely correlated with BMI-z score (r = -0.245, P < 0.01), and positively associated with endothelial MPs and platelet MPs (r = 0.230, P < 0.01 and r = 0.302, P < 0.01). Both plasma TREM-1 and pentraxin-3 levels were independently associated with AHI in multivariate models after controlling for age, sex, race, and BMI-z score (P < 0.001 for TREM-1 and P < 0.001 for pentraxin-3). However, no significant associations emerged between TREM-1, pentraxin-3, and endothelial function.

CONCLUSIONS

Plasma TREM-1 and pentraxin-3 levels are elevated in pediatric OSA, and may play a role in modulating the degree of systemic inflammation. The short-term and long-term significance of elevated TREM-1 and pentraxin-3 in OSA-induced end-organ morbidity remains to be defined.

Usefulness of serum neopterin levels in acute decompensated heart failure to predict renal dysfunction

CONTEXT

Neopterin serum concentration increases in the presence of renal dysfunction.

OBJECTIVE

We sought to determine the relationship between admission serum neopterin levels and worsening renal function (WRF) in patients with heart failure (HF).

METHODS

We prospectively measured serum neopterin levels in patients with HF and the patients were subdivided into two groups: with and without WRF during hospital admission.

RESULTS

Logistic regression analysis showed that high serum neopterin levels at admission were associated with a greater likelihood of developing WRF.

CONCLUSIONS

Patients admitted to hospital with HF, elevated serum neopterin levels are associated with an increased risk of developing WRF.

IL-17 induces apoptosis of vascular endothelial cells: a potential mechanism for human acute coronary syndrome

Th17 cells producing IL-17 are involved in the pathogenesis of atherosclerosis, but the underlying mechanisms remain unclear. In this study, we investigated the effects of IL-17 on human vascular endothelial cells and showed that IL-17 induced cell death of the vascular endothelial cells, which played a pivotal role in plaque destabilization triggering acute coronary syndrome (ACS). We showed that circulating Th17 cells and IL-17 increased in patients with ACS compared to the patients with stable angina or health individuals; the plasma levels of IL-6 increased but TGF-β decreased in ACS patients, exhibiting a positive and negative correlation with that of IL-17, respectively. Importantly, we uncovered that IL-17 promoted the production of von Willebrand factor by endothelial cells and induced endothelial apoptosis by activating caspase-3, caspase-9 and up-regulating the ratio of Bax/Bcl-2, indicating the function of IL-17 in vascular endothelial damage as a potential mechanism for the pathogenesis of human ACS.

Interrelation between arterial inflammation in acute coronary syndrome and circadian variation

At present, the study into inflammatory markers has become a new tool which is most useful for establishing the prognosis of patients with acute coronary syndrome. The inflammatory substrate involved is acute coronary syndrome is extremely complex, with a large number of factors involved both in its activation and its modulation. It is known that C-reactive protein play a key role in the physiopathology of the atherosclerosis. Furthermore, scientific literature reports that the existence of a circadian rhythm in the triggering of cardiovascular accidents can suggest the implication of, or association with these physiological rhythms that show activity peaks at particular times of the day or night. Keeping in mind the potential association between inflammation and circadian rhythm, a better understanding of the kinetics of said markers could lead to improvements in their use in cardiovascular diseases. Considering the diversity of the diurnal variations in the intrinsic properties of the cardiovascular system, these should be kept in mind during the design of in vivo experimental studies. As such, the information available reinforces our opinion when suitably validating the biomarkers and the need to demonstrate their reliability, stability, and lack of variability and standardise the methodology of their measurement.

Elevated circulating soluble form of CD40 ligand in patients with cardiac syndrome X

BACKGROUND

The presence of effort induced angina, positive exercise stress test responses and angiographically normal coronary arteries defines cardiac syndrome X (CSX). Its pathogenesis, although mostly attributed to endothelial dysfunction and coronary microcirculation abnormalities, is incompletely understood. The soluble CD40 ligand (sCD40L) has multiple autocrine, paracrine and endocrine actions that may lead to endothelial dysfunction and atherothrombosis. We sought to investigate the relationship among sCD40L levels and ischemic burden in patients with CSX and whether sCD40L levels are increased in patients with CSX compared to control subjects.

METHODS

We assessed 30 prospectively enrolled patients with CSX and 28 apparently healthy subjects matched for coronary risk factors. All CSX patients and control subjects underwent myocardial perfusion scintigraphy. The summed difference score is taken to be an index of ischemic burden. This was classified as mildly, moderately and severely abnormal. White blood cells, sCD40L and C-reactive protein (CRP) concentrations were measured at peak exercise.

RESULTS

At peak exercise, sCD40L levels were significantly greater in CSX patients than in the control group (P=0.008). Similarly, white blood cell count and CRP levels were higher in patients with CSX than in normal controls (P=0.02). After multivariable adjustment, sCD40L (P=0.03) was the only independent predictor of severe ischemic burden in CSX patients.

CONCLUSIONS

The present study showed for the first time that sCD40L is associated with ischemic burden in patients with CSX. The potential role of this inflammatory molecule in the pathogenesis of CSX deserves investigation in future studies.

Melatonin and circadian biology in human cardiovascular disease

Diurnal rhythms influence cardiovascular physiology, i.e. heart rate and blood pressure, and they appear to also modulate the incidence of serious adverse cardiac events. Diurnal variations occur also at the molecular level including changes in gene expression in the heart and blood vessels. Moreover, the risk/benefit ratio of some therapeutic strategies and the concentration of circulating cardiovascular system biomarkers may also vary across the 24-hr light/dark cycle. Synchrony between external and internal diurnal rhythms and harmony among molecular rhythms within the cell are essential for normal organ biology. Diurnal variations in the responsiveness of the cardiovascular system to environmental stimuli are mediated by a complex interplay between extracellular (i.e. neurohumoral factors) and intracellular (i.e. specific genes that are differentially light/dark regulated) mechanisms. Neurohormones, which are particularly relevant to the cardiovascular system, such as melatonin, exhibit a diurnal variation and may play a role in the synchronization of molecular circadian clocks in the peripheral tissue and the suprachiasmatic nucleus. Moreover, mounting evidence reveals that the blood melatonin rhythm has a crucial role in several cardiovascular functions, including daily variations in blood pressure. Melatonin has antioxidant, anti-inflammatory, chronobiotic and, possibly, epigenetic regulatory functions. This article reviews current knowledge related to the biological role of melatonin and its circadian rhythm in cardiovascular disease.

Evaluation of serum soluble OX40 ligand as a prognostic indicator in acute coronary syndrome patients

BACKGROUND

Long-term risk stratification in patients presented with acute coronary syndromes (ACS) is possible by measuring cardiac troponin (cTn). The present study evaluates the clinical predictive value of increased serum soluble OX40 ligand (sOX40L) in patients with ACS and acute chest pain.

METHODS

The levels of serum soluble OX40L were measured by ELISA in patients with ACS (168) and acute chest pain (106). The platelet activation was assessed by flow cytometry.

RESULTS

The levels of serum soluble OX40L were increased (> 40.0 ng/ml) in 56 patients with ACS (33.3%) and in 17 patients with acute chest pain (> 40.0 ng/ml), respectively. The increased sOX40L level was significantly correlated with measured levels of troponin I (r = 0.47, p < 0.001) and the increased soluble OX40L levels (> 40.0 ng/ml) were associated with higher risk for acute myocardial infarction (AMI), sudden death and recurrent angina. Both increased serum levels of sOX40L and cTnT showed a significantly increased risk of major adverse cardiovascular events (including AMI, sudden death and recurrent angina) in two groups during 30 days, 6 months and 9 months of follow-up.

CONCLUSION

In patients with ACS, elevation of baseline sOX40L levels indicates an increased risk for cardiovascular events. Serum soluble OX40L might be a useful prognostic marker or indicator for adverse events in patients with ACS.

Neopterin predicts left ventricular remodeling in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Left ventricle remodeling (LVR) is a relatively common and unfavourable event occurring after acute myocardial infarction. A link exists between inflammation and LVR. Neopterin, a marker of inflammation and macrophage activation, is a predictor of left ventricular dysfunction in patients with coronary artery disease. We therefore sought to assess whether both neopterin and brain natriuretic peptide (BNP), a marker of LV dysfunction and patient outcome, correlate with LVR in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

We prospectively assessed 108 STEMI patients (age 64 + or - 11 years; 85% male) undergoing primary percutaneous coronary intervention (PCI) who were assessed echocardiographycally assessment was performed at 96 + or - 10h after the onset of symptoms and 12 month after STEMI. LVR was defined as >20% increase in LV end-diastolic volume at 12 months of follow-up compared to baseline. Neopterin and BNP serum concentrations were measured immediately before primary PCI.

RESULTS

At 1 year, 21 patients (19%) showed LVR and 87 (81%) had no LVR. Patients with LVR had higher levels of neopterin at study entry (7.45 + or - 1.04 vs 5.19 + or - 1.39 nmol/L; p<0.001). After adjustment for relevant confounders, neopterin levels were found to be an independent predictor of LVR (OR ranging from [3.10, CI 95% 1.928-4.990, p<0.001] to [3.32, CI 95% 1.999-5.532, p<0.001]). ROC analysis showed an area under the curve of 0.901 for neopterin (CI 95% 0.84-0.96, p<0.0001) compared to 0.579 for BNP (CI 95% 0.409-0.748) regarding LVR.

CONCLUSIONS

In STEMI patients undergoing primary PCI, high neopterin levels - but not BNP - predict LVR at 1-year follow-up.

Regulation of endothelial cell tetrahydrobiopterin pathophysiological and therapeutic implications

Tetrahydrobiopterin (BH(4)) is a critical cofactor for the nitric oxide synthases. In the absence of BH(4), these enzymes become uncoupled, fail to produce nitric oxide, and begin to produce superoxide and other reactive oxygen species (ROS). BH(4) levels are modulated by a complex biosynthetic pathway, salvage enzymes, and by oxidative degradation. The enzyme GTP cyclohydrolase-1 catalyzes the first step in the de novo synthesis of BH(4) and new evidence shows that this enzyme is regulated by phosphorylation, which reduces its interaction with its feedback regulatory protein (GFRP). In the setting of a variety of common diseases, such as atherosclerosis, hypertension, and diabetes, reactive oxygen species promote oxidation of BH(4) and inhibit expression of the salvage enzyme dihydrofolate reductase (DHFR), promoting accumulation of BH(2) and NOS uncoupling. There is substantial interest in therapeutic approaches to increasing tissue levels of BH(4), largely by oral administration of this agent. BH(4) treatment has proved effective in decreasing atherosclerosis, reducing blood pressure, and preventing complications of diabetes in experimental animals. While these basic studies have been very promising, there are only a few studies showing any effect of BH(4) therapy in humans in treatment of these common problems. Whether BH(4) or related agents will be useful in treatment of human diseases needs additional study.